Automatic stokes



W. LLOYD.

AUTOMATIC STOKER.

.APPLICATION FILED DEc.2,1s1s`.

Patented Feb. 3,1920.

2 SHEETS-SHEETI .www

A TTORNEYS.

w. LLo-Yn. AUTOMATIC STOKER. APPLICATION FILED DEQQZ, 1913.

Patented Feb. 3,1920.

2 SHEETS-SHEET 2.

I NVENT R Unrrnn srafrns m aufn-mmm 'WILLIAM LLOYD, OE' DRIFTN, FENNSYLVNA.

AUTOMATIC STOKER.

Application filed December 2, i513.

To (1U lli/wm 'it may concern.'

Be it known that l, limitan Lnoyn, a citizen of the United States oll America, and residing at Dritten, in the county ot Lui/.e ne and State of Pennsylvania. have invented a certain new and improved .tintoinatic Stoker, ot which the following is a speciiication.-

Wy invention relates to automatic stokers for furnaces and particularly to stokers oi the traveling grate type developed by lickly B. Coxe. rThe present invention provides certain speci tic in'iprovcinents therein pointed out in the following description and illustrated in the a@companying` drawing in which, f'

Figure l is a longitudinal section through portion ot a furnace showing niy improved stoker partially in section;

Fig. .2 is an enlarged elevation partially in section of portion of the Asrratc;

Fig. 3 is a broken plan ot a portion oit the grate bar with certain portions removed;

Fig. it is a brollzen side elevation ci the saine showing sonic ot the grate har keys in position;

Fig. 5 is a cross section through the grate baron the line i-5 o t Figi. il;

Fig. G a plan ci: one oi the keys carried by the lgrate bar;

Fig'. T is a cross section on line 7. Fig. G. through ,one of the keys;

Fig. 8 is a side elevation ot' the expansion key;

Fig. 9 is a longitudinal section on line 9, Fig". 3, through portion oi a grate har "out showing),A the expansion key and adjacent keys in position;

Fig. l0 is a longitudinal section through one ot the grate bars and adjacent niar'axnriY portions o't'the side walls ofthe furnace.

lReferring to the drawings and particu larly to Fig'. 1 thereof, the stoker to which the present invention .relates is 'here shown arranged to tire a water tube boiler. The stoker., generally represented by the reiterence A, receives coal vtroni the hopper and travels slowly the length ot thci'irfe chamber under drive ot' Athe worin gear C which in turn drives .the s} rocl et D around which the chain supported grate passes. The air blast passing` upward through the grate oars ot the stoker carries the products ot trombostion to the boiler tubes E and thence to the stack (not shovvfn) in a well 'understood inanner. 'The exhausted fuel ci: ash is discharged t0 the dump vclnite l? the grate around the sprocket D. `i

Specification of Letters Patent;

Patented Feb. 3 192).

Serial No. 804,255.

Turning to Figs. 2, 3, and el, the Stoker comprises a series ot transverse grate bars, each comprising relatively heavy end blocks '20k-202, and an intermediate depressed web 20, which constitutes the body of the bar and carries a bank otl keys (hereinafter described) forming the grate bar top, on which the fuel is supported. Fach end block of the grate bar has a downwardly extending chain lug which passes through. a link in one of the customary side chains 2l and is secured thereto by a bolt 23. These lugs 29. may be casty integral with the end blocks of the grate bars. or they may be secured thereto as shownj by means of boltsel with countersunk heads. One of the end blocks7 viz., 201, is provided, on its upper tace, with a shoulder which torni-s the marginal. support of the fuel bed carried by the grate, While the portion of the end block extending outward beyond the shoulder, passes beneath the inasonry work at the side of the tire chan'iber, which thus protects the ends oit the bar and the subjacent chains from the heat of the lire. The other end block 202 has no shoulder, but its upper .tace is substantially dat. and the expansion .key 27 (hereinafter described) Yrides thereon. Both. end blocks are provided with rearwardly extending aprons 41a, and the forward. margins of the blocks are recessed to accommodate like aprons on the end blocks of the adjacent bar (see Fig. E) corresponding in this iliarticular to the outline of the grate bar keys. The apron ot' the end block 202 is recessed at, 26 to accoininodate the apron of the expansion key' 9.7. The depressed keyesupporting' web.' which extends between the. end. lblocks, is perforated, as at 2S, to permit the. upw; i'iow ot' air trom the blast` to the tuei bed resting on the keys. @n this web is formed or secured a skeleton dovetail or undercut rib 29, which extends the major portion of the length of the bar. lllongated apertures 30 oit the rib communicate with subjacont perorztions in the web to admit. the biast as freely as possible to the portion of the fuel bed oven lying the rib.

rThe fuel-supporting surface oit the grate istorincd by successive banks o'f grate bai keys 3i, one bank being carried by each grate.

er, then successively 'in alineinent .with the ico' sliding the key onto the i'ib lengthwise of the bar. After the rib 29 has been thus filled, the key bank is completed by adjusting the expansion key 27.

The expansion key comprises a shoulder' 34 which-corresponds to the shoulder 25 of .the end block 201 at the opposite end of the bar and forms, in like manner, a marginal support for one side of the fuel bed. This shoulder rides upon the upper surface of the Hat end block 202 of the bai, and the body of the key is recessed to permit it to slide thus lengthwise of the bar. The outer end of the block 202 beyond the expansion key 27 vpasses underl the masonry work of the fire chamber in like manner. as the outer end of the block 201. The apron of the key rests in thel recess 26 in the end block above mentioned and corresponds in curvature to the apron 41a of the end block and to the apron of the key bank.

Inasmuch as the rib 29 of the grate bar doesnot extend into the space 33, it is substituted at this point by a bolt 29" passing through the hole 3G in the responding to that of the rib 29. The head of the bolt isfirst passed into the undercut groove in the lower margin of the expansion key, and the latter then lowered into position, the shank of the bolt passing through the hole 36 in the bar. A nut 37, screwed i. onto the lower end ofthe bolt below the assures the close contact of the keys in thebapk, while, at the same time, permitting` the expansion of the key bank under vthe heat of the fire bed and the contraction thereof as it cools on its return travel. This feature is one of considerable importance when burning ne fuel, since the play which vwould otherwise be necessary between the keys to compensate their expansion when heated, would result in the workingV travel vof the grate being started with the keys more or less separated, and the fine fuel would fall between them and clioke'tlie air passages, thus impair-ing the efliciency of -the grate. 6o y The keys employed to form the mid portion-or body of the key bank, also present certain features of novelty. One of the principal` improvements is found in the apron 41 at the rear or following end of each key. This apron is extended reargrate bar and having a head 29 of dovetail contour, cor-- `sion, the coal sifts Wardly beneath the forward key oi ine succeeding bank a distance such that, when the key banks separate as they round the sprocket D at the end of the working travel of the grate, the rear edge of the apron underlies the forward edge of the following key, so that the ash which falls between the key banks as they separate drops upon the apron and is thus kept from entering the air spaces of the inverted grate bars below and choking` them. The apron is preferably concaved to form a trough for the reception of the ash 'and keeps the latter from scattering, as above stated. the bar are also provided with aprons 41 which register with those of the key banks, thus making a continuous ash trough not only across the entire width of the fuelL supporting area of the grate, but also be yond the ends of this area. f

A second feature of improvement is found in the longitudinal arching of the upper faces 42 of the keys. This has the eli'ect of forming an uneven surface for the grate, so that it exerts a drag on the fuel at the bottoin of the hopper B. It is found that, with the key banks thus shaped, no stirrer or other device is required to insure the proper feed of the coal to the grate as has been heretofore required when using fine coal and the fiat keys heretofore commonly employed.

A third feature of improvement is found in the transverse slots 43 in the upper faces of the keys. These slots have the triple function of (a) forming a serrated grate surface, which, combined with the arched .contour of the keys, insures a grip upon the coal by the grate as it travels beneath the hopper and causes a steady and even feed to the grate; (7)) distributingthe air to the fuel supported on the tops of the keys, since the slots extend completely across the latter and thus communicate with the air channels 44 between the keysincidentally, as to this feature, these air channels serve to cool the surface of the keys-and thus minimize the heat injury thereto; (c) permitting the expansion or contraction of the upper surface of the keys without material longitudinal distortion. The binding betweenv longitudinally adjacent key banks which sometimes occurs as a result of longitudinal expansion, is thus obviated, and it is possible totit the juxtaposed ends vof the keys of. adjacent banks closer together than has been possible heretofore when the longitudinal expansion The end blocks of I of the keys has had to be taken into consideration. This is a feature of Value .in hanl I dling fine coal, since where the banks must be spaced apart to provide for this expanin betweenthe keys'and is either lost or obstructs theair passages. Another feature of improvement 'in the keys 1s found in the side c0nstructiouthereof an adjacent key, widens .iownward from the fuel-supporting surface of thegrate. From this side of the key project spacing studs 48, the outer ends of which licl in a vertical plane and bear against the dat side ofthe adjacent key to form the blast passage-441 It Will be noted that the lipron 41 -'1s provldedwith a flange 49 on the same side of the key as the studs 48, so that this apron is continuous from one side 0f the bar to the other, and no interstice is permitted for the possible escape et ash between the keys into the bars below as the grate passes over the sprocket I).

The air blast is supplied to the fuel on the grate from a wind box W which is Aarranged between the upper and lower reaches of the grate and is divided by two transverse partitions 57. and 58 into three blastA chambers, each of which has an opening 59, 60, or 61, respectively, foithe radmission of the air blast. Inasmuch as it is desirable to supply the air at diierent pressures to the areas ofthe fuel bed above each chamber, it is necessaryto provide sealing means which prevents leakage between the chambers over the tops of the. partitions 57 and 58. For this purpose, the partitions are provided' with horizontal sealing plates (i2-63, upon which Athe tins 64 of the grate bars rest and across which they travel as the grate bar advances.' Similar sealingr lates 65-66 at the yopposite ends ofthe wind 0X coperate with the grate bar tins in like manner t0 prevent air leakage at vthese points. In order to render the seal etiectual at all times, each of the sealing plates is of such width in the direction of travel of the grate that before one of the grate bars has passed thereover, the succeeding bar engages the same and forms the desired seal.

In furnaces in which large coal is used, it is of n0 particular advantage to use small keys. Certain features or' construction herein described may nevertheless be advant eously incor orated in the keys employe Whatever tllieir particular design or size,notably the a )non 4-1 for catching the ash as the key banks se )arate on rounding the sprocket at the en of their working travel. In the appended claims, the word key is used therefore in a sense broad enough to cover keys of any suitable construction, such for instance, as that of the so-called grate top plates'ot the Van Vleck Patent 1,063,288.

The present construction is particularly efficient in dealing with very tine coal, since the air blast passing up through the grate bars is uniformly and evenly distributed to the grate surface through the interstices bctween the keys and the cross channels in the upper faces of the latter. The smaller grades of buckwheat coal have been successfully burned 0n the present grate, while due to the novel arched construction of the keys and their serrated surfaces, there has been no ditiiculty with the feed. The tire'burns evenly at the mid portion of the bed as well as at the edges. Again, the ash is cleanly dumped to the discharge chute without falling between the banks of the keys by reason ot the aprons 41. 'The blast distribution has been rendered effective by the sealing plates and the cooperating ribs on the grate bars, inasmuch asthe latter maintain their shape without warping, by reason of the fact, on the one hand, that the heat of the tire bed is lifted well above them, and, on the other hand, they are constantly cooled from below by the upward flow of the blast.

Various n'ioditications in detail will readily occur to those skilled in the art, which do not depart from what I claim my invention, and I do not limit myself to the illustrative details shown in the accompanying drawings and above described.

I claim as my invention 1. In an automatic stoker, an endless travcling grate con'iprising cross bars and on each bar a bank of keys, the keys ot each bank being spaced apart at their coal-supporting faces to admit air from below to the superposcd coal bed but having at their rear ends, in the direction of the working travel ot' the grate, contiguous impert'orate aprons underlying, in their extreme angular position, the forward ends ot the keys of the following bank and forming a continuous transverse apron which serves to catch the ash falling between the adjacent banks of keys as their adjactnity ends separate atthe end of the working travel ot' the grate.

2. In an automatic stoker, an endless traveling grate comprising cross bars and on each bar a bank of keys, the keys of each bank being spaced'apart at their coal supporting faces to admit air from below to the superposcd coal bed but. having at their rear ends, in the direction ot the working travel of the grate, contiguous impertorate aprons underlying, in their extreme angular position, the forward ends of the keys of the following bank and forming a continuous transverse apron which serves to catch the ash falling between the adjacent banks of keys as their adjacent ends separate at the end of the working travel of the grate-said apron being concaved to form a'receivinfg trough for'thc ash.

3. In Van automatic Stoker, an endless traveling grate comprising cross bars and on cach bar a bank of keys, each of said keys having a vertical side wall, the opposite side Wall being inclined outwardly from bottom toward the top of the key, studs projecting laterally from said inclined wall and adapted to space the key from the vertical wall of the adjacent key, together with transwall being inclined outwardly from bottoln toward the top of the key, studs projecting I laterally from said inclined wall and adapted to space the key from the vertical wall of the adjacent key, together with transverse grooves in 'the upper face of the key open- 1ng to the space thus formed between adjacent keys, together with an apron, at the rear end of the key, in th'c direction of the working travel of the grate, underlying the forward end of the corresponding key in the vfollowing bank, said apron forming with the aprons of the remaining keys of the bank a continuous following apron adapted to catch the ash falling between adjacent banks of keys as their adjacent ends separate at the end of the working travel of the grate.

5. In an automatic stoker, an endless traveling grate con'iprising perforated cross bars each having a dovetailed rib on its upper face, said rib being' centrally apertured to permit the upward flow of the blast therethrough together with a series of keys 'mounted on said rib, each of said keys havinl a dovetailed recess in its lower portion a apted'to fit said rib, lateral studs spacing saidl keys apart to admit the blast to the superposed coal bed, and at its rear end, in the'direction of the travel of the grate, an apron contiguous with the aprons of juxtaposed keys and forming a continuous apron underlying the forward end of the following bank of keys and serving to catch the ash falling between the banks on the separation of their adjacent ends at the end of the working travel of the grate.

6. In an automatic stoker, an endless traveling grate comprising a series of grate bars each having a fuel supporting face apertured to afford blast passages and an imperforate following apron underlying, in

its extreme angular position, the forward edge of the fuel-supporting surface of the succeeding grate bar and the supporting surface of the apron being concaved to form a trough serving to catch the ash fallingbetween adjacent bals as their juxtaposed edges separate at the end of the Working travel of the grate.

7 In an automatic stoker, an endless traveling grate comprising cross bars, a.

lplurality of keys mounted transversely.

slidable on each cross bar, and means carried by each bar outside the fire zone for maintaining the keys thereon constantly juxtaposed irrespective of expansion and contraction.

8. In an automatic stoker,A an endless4 travehnggrate comprising cross bars, a plu-y the keys on said bar and thus to maintain the same juxtaposed irrespective of contraction and expansion.

9. In' an automatic stoker, an endless traveling grate comprising cross bars, a plurality ot keys mounted transversely slidable on each cross bar, an expansion key on each bar, a plunger passing through the dend of the grate bar and bearing against said expansion key, a screw plug in the end of the bar and a spring interposed between said plug andplunger to force the latter against the expansion key, for the purpose described.

l0. In an automatic stoker, an endless traveling grate comprising cross bars, an undercut rib extending partially the. length of the upper face of each bar, a plurality of keys slidably engaged upon said rib, an expansion key, an independent undercut rib segment on which said expansion key is adapted to slide and means for fastening' said rib segment inl position after the keys have been adjusted upon the ribv extending' longitudinally of the bar.

1.1. In an automatic stoker, an endless traveling grate having a transverse grate bar with end blocks and an intermediate depressed section, means for mounting grate bar keys in said depressed section, one of said end blocks having a raised portion adjacent the depressed section to form a marginal support for the fire bed, while the portion of the.

end block beyond said raised portion extends` box wall when the grate is installed.

13. In an automatic stoker, an endless traveling grate comprising grate bars, a plurality of keys arranged on each grate bar, each of said keys comprising an elongated solid body having transverse serrations in its fuel-supporting face to admit -tension of said key body forming an imperforate apron of a` width greater than the fuel-supporting' surface of the key and adapted to meet the edgesof corresponding extensions on laterally juxtaposed keys to afford a continuous imperforate apron, for

the purpose described'.

15. In an automatic stoker, an endless -traveling grate comprising grate bars, a lurality of keys arranged on each grate liar, each ofsaid keys 'comprising an elongated solid body ail'ording a fuel-supporting surface, means for spacingsaid surface from' a laterally juxtaposed key on said cross bar to aiold a blast passage, and a rearward extension of said key body form ing an imperforate apron of a width greater than the fuel-supporting surface of .the key and adapted to meet the edges of corresponding extensions on laterally juxtaposed keys to afford a continuous impert'orate apron, said apron being curved to the shape of the forward end of the following key.

16. In an automatic stoker, an endless travelin-g grate comprising grate bars, a plurality of keys arranged on each grate bar, each of said keys comprising an elongated solid body affording a fuel-suporting surface, 'means for spacing said surface from a laterally juxtaposed key on said cross, bar to afford a blast passage, and a rearward extension of said key body forming an imperforate apron of a width reater than the fuel-supporting surface o the key and adapted to meet the edges of corresponding extensions on lateral juxtaposedkeys to afford a continuous imperforate apron, said apron resting upon4 the cross bar of the grate.

17. In an automatic stoker, an endless traveling rate comprising grate bars, a plurality o? keys arranged on each grate bar, each of said keys comprising an elongated solid body, s acing studs on one side of said body an a flange (49) at one end of said key and extending laterally from the body the same distance asmthe studs.

18. In an automatic Stoker, .Y an endless traveling grate comprising grate bars, a plurality of keys arranged on each grate bar, each of said keys comprising an elongated body, spacing studs and an end flange (49) projectmg from one side of said key, the outer faces of said studs and flange lying in a plane parallel with .that of the opposite side ofthe key.

' 19. In a traveling grate, the combination of a transverse grate bar, a series of inter.- mediate fuel-supporting keys arranged side by side on the grate bar, an end key on the grate bar at the end of the series of inter.- mediate keys, and means for securing the end key on the grate bar, com rising` a device connected at its lower endp to the grate bar and extending u ward into loose connection with the end ey, and springmeans yieldin ly opposing movement of said end key un( er pressure exerted laterally thereon -by the intermediate keys.

20. In a traveling grate, in combination, a transverse grate bar, a series of fuel-supporting keys arranged side by side on the grate bar, -a removable end key on said grate bar at the end of said series, and

'means for fasteningthe end key to the grate bar, comprising avertical bolt loosely connected at the top tothe end key and at the bottom to the grate bar, and a yielding de-u vice to permit lateral movement of the end` ke)Y unc er pressure thereon.

21. In a travelingv grate, a transverse grate bar having a depressed mid portion, means for mounting fuel-supporting keys side by side in. said depressed mid ortion, and an end, key overlapping the end) of the .gratebar beyond said depressed mid portion.

22. In a traveling grate, a transverse grate bar vhaving end blocks andan intermediate depressed mid portion, keys mounted side by side in said depressed mid portion and having juxtaposed following apronsA forming an ash catcher between adjacent grate bars on their angular separation at the end of the working travel of the grate, the end blocks of said grate bar having corresponding aprons l ing in regis- I ter with those of the interme iate keys.

23. In a traveling grate, a grate bar having a depressed key-supportmg web, end blocks between which said web extends, said en'd blocks having' rearwardly extending 'aprons and corresponding recesses at their forward margins to receive the apron .of the. adjacent bar in the assembled grate.

In testimony whereof I have signed my name to this specification in the presence of two subscribing witnesses.

WILLIAM LLOYD.

Witnesses: y

, Jos. C. HOFFMAN,

J. W. WILMo'r. 

